Ecosystems are always changing.
Chapter 2
Section 3
Populations change over time.

Limiting factors: any factor or condition that
limits the growth of a population in an
ecosystem
–
Examples: a large population of predators will
limit the population of prey, a large population of
prey will limit the population of predators, too
much or too little of any biotic or abiotic factor
makes an ecosystem unstable
Maintaining a balance

Carrying capacity: when a population has
reached a state where it can no longer grow
it has reached its carrying capacity
–
–
Living things have certain minimum requirements
for food, water, and living space
Different for each population
Ecosystems change over time.

Succession: the gradual change in an
ecosystem in which one biological
community is replaced by another
Primary Succession

After something like a lava flow destroys the
ecosystem Primary succession occurs which
is the establishment of a new biological
community
–
–
Pioneer species: first living things to move into a
barren environment
As the pioneers grow, they weaken the rock
surface and break the rock down, decaying plant
matter adds nutrients and forms soil allowing
more plants and shrubs to take root and support
insects, birds, and small rodents
Primary Succession
Secondary Succession


Takes place after a major disturbance to the
biological community in a stable ecosystem,
occurs after a forest fire or other natural
event
Below the surface seeds and plants survive,
after time grasses and small shrubs grow up
and small animals return, eventually large
trees return providing food for more types of
animals
Secondary Succession